If you're looking for a tough, easy-to-grow and attractive plant, a hoya (Hoya spp.) could be the perfect choice for your home or garden. The hoya plant can grow outdoors year-round in U.S. Department of Agriculture plant hardiness zones 10 through 12, but also makes a good houseplant that can move outdoors in warm months in other regions.
1. Indoor Light
The most commonly grown type of hoya is called the wax plant (Hoya carnosa), named for its waxy leaves and blossom clusters. It grows as a graceful vine with a woody stem and thick, fleshy leaves and can be trained to a trellis or other support. It also makes a pleasing display when its stems cascade over a pot's edge and are allowed to trail down. Indoors, it does best when grown in a south- or west-facing window, where it receives direct sun for several hours each day. It can tolerate less light and continue growing, but is unlikely to flower indoors without some direct sun.
2. Outdoor Light
Grown outdoors, a hoya plant does best in a spot that gets several hours of direct sun each day. Full sun for the entire day might scorch its leaves, especially in areas with hot summer sun. In these areas, a spot that gets morning sun, followed by shifting shade in the afternoon, is ideal. When grown in bright light, hoyas produce tiny pinkish flowers that resemble porcelain and appear in tightly rounded clusters of up to 30 blossoms. Although a plant that only gets indoor light is less likely to flower, moving a houseplant outdoors to a bright spot when temperatures remain above 60 degrees Fahrenheit can help it set flower buds, but you should do this gradually, adding an hour or two of exposure to outdoor light each day.
3. Soil and Water
An indoor-grown hoya does well in standard, soil-based potting soil, while one grown outdoors thrives in any type of garden soil that's well-draining. When grown outdoors, good drainage is essential for healthy root development. If your soil contains clay and holds water, add sand at planting time to improve its drainage. A hoya needs modest but consistent amounts of water from spring through fall, with the top few inches of soil allowed to dry slightly between waterings. In fall and winter when it becomes semi-dormant, water the plant only once every week or two, to give the plant a rest.
4. Other Needs
Once a hoya plant sets flower buds, do not move it or change its position because this can interrupt the flowering process. The plant uses the stem supporting each flower cluster, called the peduncle, to set the next season's buds, so allow the individual spent flowers to drop on their own and leave the supporting stem in place. For best growth, fertilize the plant every two months during spring and summer with a balanced, 10-10-10 fertilizer diluted at a rate of 1/4 teaspoon per 1 gallon of water, or one-quarter of the strength listed on the package instructions.